Safety device for conveyers



G, JOHN. SAFETY DEVICE FOR CONI/MERS.

APPLICATION FILED DEC.2?, IUI?- Patented Oct. 3, 1922.

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GRIFFITH JOHN, F YONKERS, NEW YORK, SSIGNOR TO OTIS ELEVATOR (lOllPil-MNTY,

Maaate -t'rea.-

OF JERSEY CITY, NEW J' ERSEY A CORPORATION OF NEW SJ'IlIRIfKSEY.'vr

SAFETY DEVICE FOR CONVEYERS.

application led December 22, 19174.. Serial No. 208,397.

To all whom t may comer-n:

Be it known that I, GRIFFITH JOHN, asubi ject of the King of Great Britain., residing ci ent to the load-whichmightjotherwise' in Yonkers, in the county of Westchester and State of New York, have invented a newand useful Improvement, in Safety De# vices for Conveyors, of which the following is a specilication. o o y My invention relates toy safeguarding apparatus for that class ofA conveyers used-to transport. passengers and freight from 'one point to another bymeans of a continuously.

moving support on which the loadre'sts, such support being a series of Vusections connected and propelled by means 'of a driving chain.'

The object ofy the invention is the provision in an apparatus of the classdescribed of automatic means to immediately halt the movementof the conve er in the event:A of a break 'in the 4driving c ain,'and vso prevent an further damage to the "apparatusor acresult from a continued-operation afterthe occurrence of such a break.

In the usual types `of sectionalcontinu ously moving conveyers or moving stair# ways, the only connections between the suc cessive sections are the links of the driving chain upon which fall the strain of'drawing and supporting the load in its ascent, as well.

as that strain due tofengagement with 'a driving sprocket. Consequently linksfrequently break under their severe duty2 fand 'with a continued operation ofthe driving mechanism, the conveyer is in danger ofbecoming jammed-while if the broken link isl per-.

mitted to come into engagement'with the driving sprocket or idler sprockets serious wreckage may result to the sprockets, driving chain and other parts of the conveyer, with theadded danger of an accident to the load. In my invention I meet this condition, l and attain the desired object through utilizing the broken member as a circuit maker in ran electrical device. A

' Referring to the accompanying sheet yof drawings. Fig. 1 is 'a side elevation of the essential parts of a conveyer or moving stairway in the vicinity of the driving sprocket, showing my invention embodied therewith. F ig. 2 is kaA sectional view taken on the line' ain Fig. 1. Fig. 3 is a diagrammatic side elevation of.. a complete driving chain for a conveyer showing' the relative positlon of my invention therewith.

Fig. 4 is a wiring diagram for the control of the driving apparatus of a conveyer in connectlon with the present invention. Similar characters of reference indicate like parts throu hout the several figures.

In ig. 1'a driving chain for a conveyer is composed of links 1, each comprising two shroudplates 2, connected by cross pins 3.

The links serve as connecting members be-V tween axles 4, upon whichare supported sections or steps- 5. A driving sprocket or spur wheel engages theaxles 4 and cross .pins 3 in well-known manner. I fix directly under vandpa'rallel to the upper or working runof the driving vkchain, bothaboveb and below the'driving sprocket, pairs of strips of electroconductive material 7 mounted on insulating strips 8, and supported by suitable Ybeams). rIfhepai'rsof strips are placedclose'under'the chain in such position Vthat th'ebroken members-of any link'l will drop thereonto`,'bringing the cross 'pins 3 into VContact ,with bothstripsgto completean elec -tric ci'cuit across 'the strips through the cross ins. In' the' illustration, the nearer shrou plate of link -1 'is cut away to show the position of the cross pins in contact with the strips. I find it advisable, to incline the end ofthe strips 7 to the periphery of the driving sprocket, as shown, on that side to'whichthe chain passes in itstravel after engagement with the sprocket, in order that, in the event of a link breaking while on the sprocket, the same will subsequently drop lonto the strips 7 without the danger of becoming caught under the latter. In the apparatus here shown, the arrangement is made for an ascending conveyer, yWhile for a ldescending machine the ends'of the strips .95

travel of the chain in which a broken link will drop'clear of the steps so that it may be used to complete an electric circuit. It will be seen that protection is afforded throughout the entire ascending or working trip of the chain, wherein breaks will invariably occur, since it is obviously unlikely that any break will take place on the return trip where the links are subjected to comparatively little strain.

In Fig. 4, I show a wiring diagram for a direct current electric motor, 10, and electromagnetically released brake. 11, for actuating the driving sprocket of a conveyer.A Obviously any type of motor in connection with a suitable system of wiring might be used for the purpose. A-manually closed potential switch 12 is held closed by its magnet, while a normally closed relay' switch 13 controls contacts in the circuit for the magnet of the potential switch. The upper and lower sections of strips 7 are connected in parallel, and with the cross pins 3,'constitute circuit closers for the magnet of switch 13. An accelerating switch 14 is connected in well-known manner across the armature of the motor 10 to automatically step out the resistance l5. To start the apparatus the potential switch 1 2 is thrown 1n by hand, completing a circuit for its own magnet from the plus main through the magnet, conductor 16, contacts of switch 13, conductor 17 to the minus main. Circuits -are simultaneously completed for the motor and brake. Now when any one of the cross pins 3 droR onto either pair of conductors 7, a circuit is completed for the magnet of switch 13 from the plus main, conductor 18, strips 7, cross pin 3, conductor 19, magnet 13, conductor 2O tothe minus imain. vThe operation of switch 13 opens its contacts and breaks the circuit previously traced for the magnet of potential switchA l2, causing the latter to open, stopping the motor and applying the brake. In machines designed to be operated in either di-` rection, the principle here outlined may be embodied in connection with suitable reversing switches.

It will be seen that the comparatively simple device herein described providesian adequate and reliable safe-guarding means to bring a conveyer to an immediate stop in the event of a break in the driving chain. Obviously those skilled in the art may make various changes in the constructions and arrangements of parts without departing from the spirit and scope of my invention.

' I desire, therefore, not to be limited to the exact constructions herein described.

I claim- 1. In combination, a continuously moving conveyer, actuating'apparatus therefor, and electric means comprising an open circuit adapted to be bridged to stop the actuating apparatus, said means operable by a broken partof the conveyer, said part itself adapted to serve as a. bridge for said open circuit.

2. In combination. a drive chain of a conveyer, actuating apparatus therefor. and electric means comprising an open circuit adapted to be bridged electrically to stop the actuating apparatus. said means operable by -a broken part of the'drive chain, the said part itself serving to constitute the bridge for said open circuit. l

3. In combination, a drive cha-in of a conveyer, and an electrical conductor through which an electric circuit is completed by means of a contact with a broken member ofthe chain.

4.. In combination, a drive chain of a conveyer, actuating electric motor apparatus therefor, a circuit therefor and an electrical conductor through which an electric circuit is completed to the circuit for the motor'by contact with the chain to cause the actuating apparatus to stop.

5. In combination, a drive chain of a con! veyer, actuating` apparatus therefor, an electro-responsive device. and an electrical conductor through which an electric circuit is completed by contact with the chain to cause the actuating apparatus to stop by means o f an operation of the electro-responsive device. I

6. In combination. adrive chain cfa conveyer, actuating apparatus therefor, an electro-conductive member adjacent to the chain to cause, through contact withv the latter, as accomplished by breaking of the same ai stopping of the actuating apparatus.

7. In combination, a drive chain of a conveyer, actuating apparatus therefor, an electro-conductive member extending adjacent to the chain throughout the working run 'of the latter to cause through contact with the chain, as accomplished by a breaking of the same, a stopping of the actuating apparatus.

8. In combination, a continuously moving conveyer, operating means therefor, a source of power supply. an electro-responsive device to connect the operating means to the source of power supply, a second electro-responsive device to control a circuit for the said electro-responsive device, an electrical conductive means operable by a broken part of in a moving part of the conveyer to close a circuit for the last named electro-responsive device, to open the first named circuit to disconnect the operating means from vthe source of power supply.

9. In combination with a drive'chain of a conveyer, an electric motor, an electromagnetically released brake, an electro-responsive switch controlling circuits for the motor and brake, a second electro-responsive switch controlling a circuit for. the said first mentioned electro-responsive switch, and an electrical conductor through which a cirv13o cuit is completed by electrical Contact with -responsive switch, to cause the same to open and to interrupt the circuits for the mot-01' and brake.

In testimony whereof, I have signed my name to this speccaton in the presence of two subscribing witnesses.

v GRIFFITH JOHN. Witnesses:

` ERNEST L. Guam7 Jr.,

HAZEL R. GATES. 

